Ingo Molnar reported that 'kill -3' didn't work on his machine:
* Ingo Molnar <mingo@xxxxxxx> wrote:
> This is really cumbersome to debug - is there some good way to get to the RIP
> that the guest is hanging in? If kvm would print that out to the host console
> (even if it's just the raw RIP initially) on a kill -3 that would help
> enormously.
Looks like the code should be doing that already - but the ioctl(KVM_GET_SREGS)
hangs:
[pid 748] ioctl(6, KVM_GET_SREGS
Avi Kivity pointed out that it's not safe to call KVM_GET_SREGS (or other vcpu
related ioctls) from other threads:
> is it not OK to call KVM_GET_SREGS from other threads than the one
> that's doing KVM_RUN?
From Documentation/kvm/api.txt:
- vcpu ioctls: These query and set attributes that control the operation
of a single virtual cpu.
Only run vcpu ioctls from the same thread that was used to create the
vcpu.
Fix that up by using pthread_kill() to force the threads that are doing KVM_RUN
to do the register dumps.
Reported: Ingo Molnar <mingo@xxxxxxx>
Cc: Asias He <asias.hejun@xxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Prasad Joshi <prasadjoshi124@xxxxxxxxx>
Cc: Sasha Levin <levinsasha928@xxxxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
tools/kvm/kvm-run.c | 20 +++++++++++++++++---
1 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
index eb50b6a..58e2977 100644
--- a/tools/kvm/kvm-run.c
+++ b/tools/kvm/kvm-run.c
@@ -127,6 +127,18 @@ static const struct option options[] = {
OPT_END()
};
+static void handle_sigusr1(int sig)
+{
+ struct kvm_cpu *cpu = current_kvm_cpu;
+
+ if (!cpu)
+ return;
+
+ kvm_cpu__show_registers(cpu);
+ kvm_cpu__show_code(cpu);
+ kvm_cpu__show_page_tables(cpu);
+}
+
static void handle_sigquit(int sig)
{
int i;
@@ -134,9 +146,10 @@ static void handle_sigquit(int sig)
for (i = 0; i < nrcpus; i++) {
struct kvm_cpu *cpu = kvm_cpus[i];
- kvm_cpu__show_registers(cpu);
- kvm_cpu__show_code(cpu);
- kvm_cpu__show_page_tables(cpu);
+ if (!cpu)
+ continue;
+
+ pthread_kill(cpu->thread, SIGUSR1);
}
serial8250__inject_sysrq(kvm);
@@ -332,6 +345,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
signal(SIGALRM, handle_sigalrm);
signal(SIGQUIT, handle_sigquit);
+ signal(SIGUSR1, handle_sigusr1);
while (argc != 0) {
argc = parse_options(argc, argv, options, run_usage,
--
1.7.0.4
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